This invention relates to a vehicle trailer hitch, and more particularly to a modular trailer hitch composed of extruded aluminum.
Vehicles use trailer hitches to tow trailers or other vehicles. Several different types of hitches exist, including, rear mounted, front mounted, or 5th wheel hitches. Trailer hitches must sustain shear, tensile and compressive forces. Trailer hitches are sized and manufactured to transfer forces between the vehicles to which they are connected. Trailer hitches typically have one portion that is permanently secured to a vehicle, and another portion to which the trailer is detachably secured. Some trailer hitches have a cross-beam member attached to the vehicle frame and a hitch receiver nested in the cross-beam. Prior art trailer hitches are constructed of different components, that are usually steel, and each component must be secured to others.
U.S. Pat. No. 6,669,223 (“the '223 patent”) discloses a trailer hitch having “Ends of the strut tube are flattened . . . ” as described in the abstract and in FIGS. 1 and 2 of the '223 patent. The '223 patent hitch assembly is manufactured from an extruded U-shaped tube having an oval cross-section with flattened ends housing a cast hitch receiver; thus requiring an alloy having a good formability to avoid fracture during forming operations. This is usually not obtainable with common high strength aluminum alloys. The '223 patent requires a newly formed tube for accommodating vehicles with different rail spacing. The beam is fastened to the vehicle at flattened portions (20) via bolt holes (18). Also, the '223 patent discloses a bolt connection to fasten the receiver to a frame member or bumper system. The flattened portions (20) result in the beam having a reduced mechanical moment of inertia, thus the bolted connections (through bolt holes (18)) are only effective in transferring shear loads, and primarily shear loads in the horizontal plane. The connections (using bolt holes (18)) are not effective in sustaining vertical loads. Therefore the '223 patent may require a supplementary bolted connection from the receiver to a vehicle structural member that can hold the hitch towing load in the vertical direction.
Due to the worldwide volume of motor vehicle usage, a minor decrease in the cost to produce a beam with a trailer hitch; a minor decrease in the weight of a single beam with a trailer hitch; or a minor decrease in the production time of a single beam with a trailer hitch, can be a significant savings in cost and resources.
As can be seen, there is a need for a light weight trailer hitch system with a reduced number of steps to manufacture, and a reduced cost to manufacture. There is also a need for a hitch and beam that can support shear, vertical, and horizontal hitch loads without additional supporting structures.